Crystal ball says a new slave cylinder is in the immediate future for my Defender.

Everybody keep saying one should do master and slave at the same time. But I'm inclined to start with the slave and see what happens. Any reason why not?

On a Defender Td5, the slave sits immediately above the exhaust and sees a lot of heat with a tuned engine. But it is extremely simple to replace. The master seems to be a different story, though, as it is buried deep inside with aftermarket wiring and vacuum hoses on top.

Getting lazy, are we?

The reasoning is that with new components the remaining old components see higher pressures than they have seen recently and then becomes the new weak link.

With bleeding the hydraulic system being a not insignificant part of this operation, I'd do the full swap.

At least on a series you can increase accessibility by removing the left wing.

T

Being lazy is not new to me.

Bleeding is really an insignificant operation, on a Td5 at least. So is changing the slave. I think you can do the whole thing in less than 30 minutes if you have to.

Wing removal means roll cage disassembly on mine, and a lot of other time consuming details. I would say half a day of tinkering since I haven't done it before, and need to remove a few panels just to see the thing.

Truck is only a 2001 with modest mileage (~80 000 km) and I think the slave is dying in young age due to overexposure to swamp water and heat. There is a fair chance the master is in better shape.

I guess the real question is if I can hurt a new slave by running it with an older master? Worst case should be some gunk coming downstream, but that will go out with bleeding, or?

If the salve cylinder failed due to excessive heat, it is unlikely that any damage was done to the master cylinder. Now, had this been an old series that had sat out behind the barn and not been driven much and the slave had failed, then I'd say, yes, replace both. Given the young age, it is equally unlikely that you would be exposing the master cylinder to more resistance or pressure than the previous slave cylinder would have posed/exhibited.

If you feel it is absolutly necessary, flush the system with new brake fluid, although, I'd suspect that will happen spontaneously, unless you can swap the slave cylinder faster than the fluid leaks out :flipoff2:

Given the times you quote, what has stopped you testing already!

I do not see any reason to hurt the new slave by running with a dubious old master.

T

I replaced only the slave on my Disco when the seals were damaged from exhaust heat. That was 50K miles ago and the replacement is still fine.

I do not see any reason to hurt the new slave by running with a dubious old master.

T

Unless the master is sloughing particles, how is it going to damage the slave? Based on your comments about components not tolerating increased pressures, I'd expect greater back pressure from the slave to cause premautre failure of the master, not the slave.

PT

Given the times you quote, what has stopped you testing already!

I do not see any reason to hurt the new slave by running with a dubious old master.

T

Times qouted do not include delivery time for parts I don't have. :D I have flushed the system once, hoping that bad fluid was causing the vague clutch. I haven't driven it since, and am about to tear into the diffs now, so it will be a while. My hopes that new fluid only will solve the issue is vaning, though.

Flushing is simple, and the two bolts holding the master are easy to access, as is the hydraulic line.

I would think that the clutch master would hold up at least as long as the brake master, which I expect to last a long time?

Conclusion: If you repeat the question enough times you will eventually get an answer to your liking!